11:27 a.m.
Hello everyone,
This afternoon at 13:30 in D1.14 we'll have a talk by Markus Frembs, a visitor to the
group today. I apologize for the last-minute notification, this plan only came together in
the last half hour or so! Markus' title and abstract are below.
Join us at 13:30 in D1.14 or online at https://meet.jit.si/cqi-demon-M6QW9V7YY
Best regards,
Will Schober
Title: Bipartite Entanglement and the arrow of time
Abstract:
Quantum correlations in general and quantum entanglement in particular embody both our
continued struggle towards a foundational understanding of quantum theory as well as the
latter’s advantage over classical physics in various information processing tasks.
Consequently, the problems of classifying (i) quantum states from more general
(non-signalling) correlations, and (ii) entangled states within the set of all quantum
states, are at the heart of the subject of quantum information theory.
In this talk I will present two recent results (from
https://doi.org/10.1103/PhysRevA.106.062420 and
https://doi.org/10.1103/PhysRevA.107.022218) that shed new light on these problems, by
exploiting a surprising connection with time in quantum theory:
First, I will sketch a solution to problem (i) for the bipartite case, which identifies a
key physical principle obeyed by quantum theory: quantum states preserve time
orientations—roughly, the unitary evolution in local subsystems.
Second, I will show that time orientations are intimately connected with quantum
entanglement: a bipartite quantum state is separable if and only if it preserves arbitrary
time orientations. As a variant of Peres's well-known entanglement criterion, this
provides a solution to problem (ii).